This is because when renal colic occurs, the pressure in the renal pelvis increases, and the nerves that innervate the kidney feel the stimulation and transmit it to the brain center through the abdominal nerves. The nerves in the abdominal cavity are connected to the nerves in the gastrointestinal tract, so this stimulus can cause spasmodic reactions in the gastrointestinal tract through these branches, resulting in nausea and vomiting. Therefore, in the process of acute kidney stone pain, patients can sometimes show strong vomiting, and some patients even have vomiting as the main symptom and back pain as the secondary symptom. In addition to the pain caused by kidney stones, vomiting can also be caused by acute perinephric infection and acute pressure elevation in the renal pelvis.